Three New Publications at the Open Journal of Astrophysics

It’s time for the usual  Saturday roundup of business at the  Open Journal of Astrophysics. The latest batch of publications consists of three papers, taking the count in Volume 7 (2024) up to 30 and the total published by OJAp up to 145.

First one up is “Baryonic Imprints on DM Halos: the concentration-mass relation and its dependence on halo and galaxy properties” .  The authors, Mufan Shao and Dhayaa Anbajagane of the University of Chicago, USA, use  a non-linear model informed by simulations to study the imprint of galaxy formation physics on the concentration-mass relationship using various different choices of halo selection criteria. This one is in the folder marked Astrophysics of Galaxies and was published on 24th April 2024.

Here is a screen grab of the overlay, which includes the abstract:

 

You can read the paper directly on arXiv here.

The second paper to announce is “Variability in SSTc2d J163134.1-240100, a brown dwarf with quasi-spherical mass loss” which describes a search for variability in a brown dwarf star known to be losing mass and the implications of the lack thereof for the reason for the outflow therefrom. The authors are Aleks Scholz (St Andrews, UK),  Koraljka Muzic (Lisbon, Portugal), Victor Almendros-Abad (Palermo, Italy), Antonella Natta (DIAS, Ireland), Dary Ruiz-Rodriguez (NRAO, USA), Lucas Cieza (Uni. Diego Portales, Chile), Cristina Rodriguez-Lopez (IAA-CSIC, Granada, Spain)

This one is in the folder Solar and Stellar Astrophysics and was also published on 24th April 2024. The overlay looks like this:

 

You can read this paper directly on the arXiv here.

The last paper of this batch, also in the folder marked Astrophysics of Galaxies, is  entitled “MAGICS I. The First Few Orbits Encode the Fate of Seed Massive Black Hole Pairs”  and is a computational study of the process by which massive black holes are formed by merging smaller seed black holes. It was published on April 26th 2024 (i.e. yesterday). The authors are: Nianyi Chen, Diptajyoti Mukherjee and Tiziana Di Matteo (all Carnegie Mellon University); Yueying Ni (Harvard); Simeon Bird (University of California, Riverside); and Rupert Croft (Carnegie Mellon University). All authors are based in the USA.

Here is a screengrab of the overlay:

 

To read the accepted version of this on the arXiv please go here.

That’s all for now. More news in a week or so!

 

 

Black Rook in Rainy Weather – Sylvia Plath

On the stiff twig up there
Hunches a wet black rook
Arranging and rearranging its feathers in the rain-
I do not expect a miracle
Or an accident

To set the sight on fire
In my eye, nor seek
Any more in the desultory weather some design,
But let spotted leaves fall as they fall
Without ceremony, or portent.

Although, I admit, I desire,
Occasionally, some backtalk
From the mute sky, I can’t honestly complain:
A certain minor light may still
Lean incandescent

Out of kitchen table or chair
As if a celestial burning took
Possession of the most obtuse objects now and then —
Thus hallowing an interval
Otherwise inconsequent

By bestowing largesse, honor
One might say love. At any rate, I now walk
Wary (for it could happen
Even in this dull, ruinous landscape); sceptical
Yet politic, ignorant

Of whatever angel any choose to flare
Suddenly at my elbow. I only know that a rook
Ordering its black feathers can so shine
As to seize my senses, haul
My eyelids up, and grant

A brief respite from fear
Of total neutrality. With luck,
Trekking stubborn through this season
Of fatigue, I shall
Patch together a content

Of sorts. Miracles occur.
If you care to call those spasmodic
Tricks of radiance
Miracles. The wait’s begun again,
The long wait for the angel,

For that rare, random descent.

by Silvia Plath (1932-63)

Revolução dos Cravos

My office mate in Barcelona is Portuguese and he very proudly reminded me this morning that today, 25th April 2024, is the 50th anniversary of the Carnation Revolution that ultimately overthrew a fascist dictatorship and led Portugal towards becoming a progressive democracy. Just over a year later, General Franco died and Spain began its transition to democracy too. Both countries joined the European Community in 1986 and are now members of the European Union. It’s hard to believe, only 50 years on, that fascism is on the rise once more in Europe (and elsewhere). That makes it all the more important to remember the struggles of the not-so-distant past.

The signal for the Revolução dos Cravos in Portugal to begin was a song played on the radio. The result was remarkable. Although led by military officers dissatisfied with the ruling regime, it garnered a huge level of popular support and morphed into a coordinated campaign of mass civil resistance. When regime change was achieved, it was largely peaceful. The name “Carnation Revolution” refers to the flowers given to soldiers by people celebrating their liberation from authoritarianism.

Fascismo nunca mais! Vinte e cinco de abril sempre!

I couldn’t help sharing the song that triggered that huge historical moment. It is Grândola, Vila Morena by Zeca Afonso. Few people can lay claim to have written a song that brought down a dictatorship.

.Astronomy

So here I am at the European Space Astronomy Centre (ESAC) just outside Madrid for a conference called .Astronomy 13. It is (obviously) the thirteenth such conference but the first that I have attended. I’m giving a plenary talk in half-an-hour or so. I travelled from Barcelona by train yesterday evening, which was a comfortable and uneventful trip, the (approximately) 504 km from Barcelona to Madrid Atocha station taking about 2 hours and 30 minutes that cost about 30 euros. I stayed overnight in Madrid and took a shuttle bus from to ESAC. The only glitch in my travels so far was that I got on the Metro Line 6 (the equivalent of the Circle Line), but chose the wrong platform and went the long way round. I still got there in time to get the shuttle.

Incidentally, ESAC hosts the European Space Operations Centre (ESOC) which plays a central role in the processing of data from Euclid and is also responsible for the development and operations of the Euclid Archive from which data will be distributed to the global astronomical community.

UPDATE: Back in Barcelona. The return by train was just as smooth an uneventful as the outbound journey, and in fact arrived back about five minutes ahead of schedule. Thanks to the organizers for inviting me – I’m sorry I couldn’t stay for longer as I like the idea of the .Astronomy meetings. Perhaps we should have one in Ireland sometime?

Diada de Sant Jordi

Today, 23rd April, is Diada de Sant Jordi (Saint George’s Day) which, though not a public holiday, is a very special occasion in Barcelona. Saint George is of course familiar to me as the Patron Saint of England, and of quite a few other places, but wasn’t aware until a few weeks ago that he is also the Patron Saint of Catalonia.

Not much is known about Saint George, but it is believed that he was born in Cappadocia (modern-day Turkey, then part of the Roman Empire) to parents of Greek origin, and that he fought in the Roman army and died in 303 AD in Syria Palaestina (also part of the Roman Empire). There is no evidence that he ever visited England or Catalonia for that matter. It seems that he began to be venerated around about the time of the First Crusade, which happened over seven hundred years after his death.

Anyway, the Festa de Sant Jordi is celebrated in a very civilized and charming way in Barcelona. Traditionally the celebration involved giving gifts of flowers (especially roses) to women and gifts of books to men. That is obviously a bit sexist so nowadays you can give flowers and books to whomever you wish. In order to facilitate this, quite a large area of the Eixample district around my apartment is largely closed off to traffic today, refuse collections have been paused, and there are stalls selling books or flowers filling up the pavements. It was especially busy this morning on Passeig de Gràcia, where the combination of queues at the bookstalls and queues for the Casa Batlló generated a big crowd, but the atmosphere was very friendly and nice (apart from a few car drivers upset at the road closures).

Here are a couple of video clips which will hopefully give you an idea of what it was like:

Diada de Sant Jordi

And here are some random pics

I wish I could visit the celebrations again, but this afternoon I have to take the train to Madrid for a conference.

Problematic Pollen

Four years ago, in the early months of the pandemic, back in April 2020 I wrote a post that mentioned an allergy I thought was due to tree pollen which I had noticed taking walks for exercise around the deserted Maynooth University campus. I hadn’t experienced such a thing before but didn’t know whether I had developed it in later life or whether I’d just never previously been exposed to the source. I did subsequently discover, by experimentation, that the culprit was oak pollen.

Well, for the last couple of weeks I have been suffering from a similar, but rather more severe, form of allergic reaction which I assumed was caused by tree pollen. This one doesn’t just provoke sneezing but also makes my eyes go red and watery. There are many trees of different types in the streets of Barcelona. For example, the road on which I live, Rambla de Catalunya, is lined with Lime trees (Linden); these don’t cause a reaction. Another common species is the Plane (Sycamore) and that’s OK for me too.

To identify the culprit I did some experiments similar to what I did four years ago. This wasn’t too difficult because particular streets seem to have been planted with particular trees. And so it came to pass that I soon identified the culprit, Quercus Ilex, of which there are few in places near me, including Passeig de Gràcia and Plaça de Catalunya, as seen here:

Quercus Ilex

Quercus Ilex is the botanical name for the Holm Oak (or Holly Oak), an evergreen member of Oak family in contrast to the English Oak (Quercus Robur) which is deciduous. So it seems that pollen of the genus Quercus produces a quirk of my immune system…

Why you and your institution should leave X/Twitter

Some time ago I wrote a post asking why universities are still using X, the social media platform that used to be called Twitter. In the same vein I thought I would repost the article below, which I saw this morning.

You are the fuel that energises Elon Musk’s hate machine

Two New Publications at the Open Journal of Astrophysics

It’s Saturday, and it’s time to post another update relating to the  Open Journal of Astrophysics.  Since the last update we have published two more papers, taking  the count in Volume 7 (2024) up to 27 and the total published by OJAp up to 142.

The first paper of the most recent pair – published on  Tuesday April 16th – is “An Enhanced Massive Black Hole Occupation Fraction Predicted in Cluster Dwarf Galaxies” by Michael Tremmel (UCC, Ireland), Angelo Ricarte (Harvard, USA), Priyamvada Natarajan (Yale, USA), Jillian Bellovar (American Museum of Natural History, New York, USA), Ray Sharma (Rutgers, USA), Thomas R. Quinn (University of Washington, USA). It presents a  study, based on the Romulus cosmological simulations, of the impact of environment on the occupation fraction of massive black holes in low mass galaxies. This one is in the folder marked “Astrophysics of Galaxies“.

Here is a screen grab of the overlay which includes the abstract:

 

You can click on the image of the overlay to make it larger should you wish to do so. You can find the officially accepted version of the paper on the arXiv here.

The second paper was published on Wednesday 17th April and has the title “A 1.9 solar-mass neutron star candidate in a 2-year orbit” and the authors are: Kareem El-Badry (Caltech, USA), Joshua D. Simon (Carnegie Observatories, USA), Henrique Reggiani (Gemini Observatory, Chile), Hans-Walter Rix (Heidelberg, Germany),  David W. Latham (Harvard, USA),  Allyson Bieryla (Harvard, USA),  Lars A. Buchhave (Technical University of Denmark, Denmark),  Sahar Shahaf (Weizmann Institute of Science, Israel),  Tsevi Mazeh (Tel Aviv University, Israel), Sukanya Chakrabarti (University of Alabama, USA), Puragra Guhathakurta (University of California Santa Cruz, USA), Ilya V. Ilyin (Potsdam, Germany), and Thomas M. Tauris (Aalborg University, Denmark)

This one, which is in the folder marked Solar and Stellar Astrophysics, presents a discussion of the discovery of a 1.9 solar mass neutron star candidate using Gaia astrometric data, together with the implications of its orbital parameters for the formation mechanism.

Here is a screen grab of the overlay which includes the abstract:

 

 

 

You can click on the image of the overlay to make it larger should you wish to do so. You can find the officially accepted version of the paper on the arXiv here.

That concludes this week’s update!

An Unmarked Anniversary

I didn’t have time to mention yesterday, 18th April 2024, that it was the 75th anniversary of the day that that the Republic of Ireland came into existence. The  Republic of Ireland Act, which provided the legal basis for the establishment of a new Republic, was passed in 1948 but only came into force on 18th April 1949. From that point the Republic no longer had the British monarch as Head of State and was no longer part of the Commonwealth.

That day was marked with parades and celebrations but “Republic Day” never became the public holiday that might have been expected given how many other countries mark such events in their history and indeed is hardly marked at all, not even on its 75th anniversary. I have quite a few Irish friends who were unaware of the significance of yesterday’s date.

The reason is probably explained by the statement made by Éamon De Valera when he declined an invitation extended to him by Taoiseach John A. Costello to attend the official ceremonies on 18th April 1949:

Celebrations such as those now proposed ought to be reserved until the national task which we have set ourselves is accomplished…We still believe that public demonstrations and rejoicings are out of place and are likely to be misunderstood so long as that task remains uncompleted and our country partitioned.

The Inaugural Euclid Spain Meeting

So here I am at the Institut de Ciencies de L’Espai (ICE-CSIC) which is on the campus of the Universidad Autónoma de Barcelona (UAB) for the first ever Euclid Spain Meeting. This involved a 40-minute trip on the S2 train from Plaça de Catalunya, which is a short walk from my apartment, then a short walk from the railway station at UAB through the campus to the Institute.

I was able to speak at this meeting because I happen to be in Barcelona right now. I mean that I was able to attend because I was in Barcelona anyway, not that the meeting was held because I am in Barcelona!

Anyway, I gave my talk early on this morning, so have been able to enjoy the rest of the day having got that out of the way. There are about 50 people here. It’s great to see the sizable Euclid community in Spain getting together and sharing their work.

The Inaugural Euclid Spain Meeting

P.S. My surname always causes some amusement in Spain, as “Coles” means “Cabbages” in Spanish…